Vapor compression type air conditioning systems are well known and widely used for controlling temperature in residential and commercial applications. In addition to the sensible temperature within the space controlled by a vapor compression type air conditioning system, it is usually desirable to also control the absolute and relative humidity to enhance the comfort of occupants of the space or to meet other requirements of temperature and humidity within the space.
A type of vapor compression air conditioning system has been developed wherein an additional heat exchanger is placed in the supply air flowpath which furnishes condition air to the space being controlled so that, in addition to cooling the supply air to reduce the absolute humidity, the supply air is then reheated to a desired temperature for comfort and wherein the relative humidity is then also reduced for comfort and for meeting certain other requirements of the controlled space. However, known types of vapor compression air conditioning systems which include so-called condenser reheat, wherein the added heat exchanger mentioned above is disposed downstream of the evaporator or cooling type heat exchanger, are not capable of providing a suitably wide range of dehumidification of the controlled space.
Still further, in applications of vapor compression type air conditioning systems which function as so called heat pumps, to provide both heating and cooling effect to a controlled space, there has been the same need to provide enhanced dehumidification of the supply air to the controlled space. In accordance with the present invention, vapor compression air conditioning systems, including reversible or so called heat pump type systems, are provided with enhanced dehumidification capability.
The present invention provides an improved vapor compression type air conditioning system which is capable of providing a wide range of dehumidification of supply air which is conditioned and directed to a controlled space.
In accordance with one important aspect of the present invention, a vapor compression type air conditioning system is provided which includes a conventional evaporator or cooling heat exchanger together with a second heat exchanger disposed downstream, with respect to the direction of flow of supply air, for reheating the supply air to provide air to a controlled space at a desired temperature and relative humidity. A system in accordance with the invention is capable of providing supply air to a controlled space wherein the sensible to total cooling ratio of the system can be varied over a wide range. Moreover, the system of the invention may be arranged such that only two conduits are required for interconnecting the so called indoor heat exchangers with a compressor and primary condenser unit which are disposed xe2x80x9coutdoors.xe2x80x9d
In accordance with another aspect of the present invention, an air conditioning system with enhanced dehumidification of supply air to a controlled space is provided wherein heat exchange by the primary condenser for the system is varied in accordance with the amount of heat exchange required by a supply air reheat heat exchanger which is disposed downstream of the system supply air cooling heat exchanger or evaporator. In a preferred embodiment, a variable speed fan is operable to control heat exchange between ambient air and refrigerant fluid flowing through the primary condenser heat exchanger. Still further, operation of the primary condenser heat exchanger is enhanced by allowing refrigerant fluid to bypass the primary condenser heat exchanger under certain operating conditions.
In accordance with yet a further aspect of the present invention, a vapor compression type air conditioning system is provided with at least some of the inventive features described above and which is also operable as a heat pump.
The above-mentioned advantages and superior features of the invention together with other important aspects thereof will be further appreciated by those skilled in the art upon reading the detailed description which follows in conjunction with the drawings.